The subject matter herein relates generally to sensors for detecting relative angles between two or more components.
Relative angle sensors, also referred to as angular position sensors and rotary position sensors, are used in various automotive and industrial sensing applications, such as electronic power steering systems, throttle position systems, fuel tank float-level systems, power seat and power mirror systems, flow meter systems, robotic systems, and the like. For example, in automotive electronic power steering systems, relative angle sensors are used to detect an amount of torsion (or a shift angle) between an input shaft coupled directly or indirectly to a steering wheel and an output shaft coupled direction or indirectly to a wheel of an automobile. Since the wheel is in contact with a road surface, friction between the wheel and the road causes a difference in a rotational angle (or a relative angle) between the input shaft coupled to the steering wheel and the output shaft coupled to the wheel during a turn, for example. Electronic power steering systems include relative angle sensors to measure or detect the relative angle of the shafts. The electronic power steering systems further include an electric motor or another power unit that supplies a supplemental rotational force to the output shaft coupled to the wheel. The amount of rotational force supplied to the output shaft may correspond to the measured relative angle in order to compensate for the amount of rotational lag or deflection experienced by the output shaft, with the result that the automobile may be safely and accurately steered in a desired direction.
Some known relative angle sensors include a stator divided into separate upper and lower parts connected to a first shaft, and a magnetic rotor located between the upper and lower stator parts and connected to a second shaft. The stator parts are used to route magnetic flux through a collector unit that provides a path for magnetic flux to be routed across and measured by a sensor on the collector unit. The angle sensors may be relatively complex, since each of the separate and discrete upper and lower stator parts must be mounted to the same first shaft. In addition, the upper and lower stator parts may have protrusions that must be staggered or otherwise spaced apart at precise pre-defined distances, which further complicates separately installing the upper and lower stator parts to the first shaft. A need remains for a relative angle sensor that is less complex and functions accurately to measure a relative rotational position of a first shaft and a second shaft.